Due to the invasiveness, health risks, and imperfect diagnostic accuracy of liver biopsy, as well as the availability of diagnostic imaging techniques, a large proportion of HCC is not histologically confirmed. Furthermore, most HCC patients present at an advanced stage with limited or no treatment options, precluding extensive clinical work-up. In the combined SEER registries in 2005, only 61% of newly diagnosed liver cancer cases were confirmed by positive histology. By comparison, 98% of breast, 97% of prostate, and 97% of colorectal cancers were confirmed by positive histology. Because a high proportion of tumors are identified by cancer registries based on pathology reports, increasingly so with the incorporation of electronic pathology-based reporting, HCC cases may evade routine mechanisms of cancer surveillance. These cases may be identified later through death certificate follow-back at higher overall cost, worse timeliness, and possibly with an incomplete cancer registry record.